Method for creating inter-domain bidirectional tunnel, communication method and device, and storage medium

ABSTRACT

Provided is a method for creating an inter-domain bidirectional tunnel. The method includes: receiving, by a node, a path creation message sent by a path computation element, the path creation message including mapping path information for creating an inter-domain label switched path (LSP), and bidirectional tunnel instruction information, and obtaining, by the node, an actual transmission path, which is used for data transmission between intra-domain or inter-domain nodes, based on the mapping path information and the bidirectional tunnel instruction information. The present disclosure further provides a communication method, a communication device, and a computer-readable storage medium.

TECHNICAL FIELD

The present disclosure relates to, but is not limited to, the field ofnetwork communication technology.

BACKGROUND

Segment Routing (SR), which is a source routing technology, guidesforwarding of a packet by pushing a string of ordered labels (segments)on a source node, and can conveniently realize, with an SR-specifiedpath forwarding function, load balancing and traffic engineering of anetwork and complex network functions such as fast reroute protectionirrelevant to topology.

SR supports forwarding on Multiprotocol Label Switching (MPLS) dataplane and forwarding on Internet Protocol Version 6 (IPv6) data plane,and is completely compatible with and inherits the MPLS forwarding/dataplane in MPLS scenarios, and SR forwarding can be implemented with noneed to modify an MPLS packet header. Compared with conventional MPLSsolutions, SR has the advantages that an SR control plane is moresimplified and totally based on distributed routing protocols, and canachieve segment distribution through simple extension of InteriorGateway Protocol (IGP).

Segments represent the information of network topology (nodes or links),and end-to-end connection is represented by a group of ordered labelstacks. For realizing the extension of an MPLS network, the nodes onlyneed to maintain topology information, but do not need to maintainstates of connection. Based on existing operations, an end-to-end pathcan be created through operations on a head node alone, which greatlyincreases efficiency of service deployment.

In order to implement the traffic engineering of an SR network, it isoften necessary to deploy a centralized controller or a path computationelement (PCE) to perform constrained path computation according tobandwidth, cost, label resources, and the like of the entire network, soas to achieve global optimization of traffic.

PCE Communication Protocol (PCEP) is a path computation protocol widelyapplied to networks, and can also be used as a southbound interfaceprotocol of an SR controller. In order to support SR tunnels, theInternet Engineering Task Force (IETF) extends the PCEP indraft-ietf-pce-segment-routing. It is defined in the draft that a PathComputation Client (PCC) and a PCE perform capability negotiation on thePCC and PCE through Open message during the initialization of a PCEPsession. If the negotiation is successful, an SR tunnel can be createdthrough the PCEP, so as to support deployment requirements of SR incontroller scenarios.

The SR technology can be applied to IPRAN (IP Radio Access Network),MPLS-TP, metropolitan area network, data center interconnection, etc. Inthe case of being applied to an MPLS-TP network, the SR technology needsto be extended to support the creation of a bidirectional tunnel. Abidirectional tunnel can be created by associating unidirectionaltunnels in the conventional MPLS technology. For an SR tunnel, thestates of connection are maintained only on the head node, and the tailnode does not carry any connection information, which makes itimpossible to associate and bind two unidirectional tunnels at both endsof the tunnels, resulting in the limitation of the application of SR. Asshown in FIG. 1, the IETF provides an extension to SR for applicationsof transport networks in draft-cheng-spring-mpls-path-segment-00, anddefines a Segment Routing Transport Profile (SR-TP) tunnel for thetransport networks. A Path SID is introduced to identify an SR Path, andbidirectional binding is realized. Serving as an SR Path identifier, thePath SID is located after a last SR Segment, and the nodes at both endsof an SR Path need to maintain a mapping relationship between SR pathinformation and the Path SID, so as to realize the binding of abidirectional tunnel.

SUMMARY

The embodiments of the present disclosure provide a method for creatingan inter-domain bidirectional tunnel, a communication method, acommunication device, and a computer-readable storage medium.

The embodiments of the present disclosure provide a method for creatingan inter-domain bidirectional tunnel, including: receiving, by adomain-boundary node, a path creation message which is sent by a PCE ora hierarchical path element and includes mapping path information forcreating an inter-domain label switched path (LSP) and bidirectionaltunnel instruction information; and obtaining an actual transmissionpath, which is used for data transmission between intra-domain orinter-domain nodes, based on the mapping path information and thebidirectional tunnel instruction information.

The embodiments of the present disclosure further provide acommunication method for an inter-domain bidirectional tunnel,including: receiving, by a domain-boundary node, a path creation messagewhich is sent by a PCE or a hierarchical path element and includesmapping path information for creating an inter-domain LSP andbidirectional tunnel instruction information; obtaining an actualtransmission path based on the mapping path information and thebidirectional tunnel instruction information; and sendingto-be-transmitted data by the domain-boundary node to a next node basedon the actual transmission path.

The embodiments of the present disclosure further provide a device forcreating an inter-domain bidirectional tunnel, including a receivingmodule configured to receive a path creation message which is sent by aPCE or a hierarchical path element and includes mapping path informationfor creating an inter-domain LSP and bidirectional tunnel instructioninformation; and a path creating module configured to obtain an actualtransmission path, which is used for data transmission betweenintra-domain or inter-domain nodes, based on the mapping pathinformation and the bidirectional tunnel instruction information.

The embodiments of the present disclosure further provide acommunication device for an inter-domain bidirectional tunnel, includingthe above device for creating an inter-domain bidirectional tunnel, anda data transmission unit; the device for creating an inter-domainbidirectional tunnel is configured to receive a path creation messagesent by a PCE or a hierarchical path element, where the path creationmessage includes the mapping path information for creating aninter-domain LSP and the bidirectional tunnel instruction information,and obtain an actual transmission path based on the mapping pathinformation and the bidirectional tunnel instruction information; andthe data transmission unit is configured to transmit to-be-transmitteddata from a current node to a next node based on the actual transmissionpath.

The embodiments of the present disclosure further provide acommunication device, including a processor, a memory, and acommunication bus; the communication bus is configured to implementcommunication connection between the processor and the memory; theprocessor is configured to execute one or more first programs stored inthe memory to perform the steps of the above method for creating aninter-domain bidirectional tunnel; or the processor is configured toexecute one or more second programs stored in the memory to perform thesteps of the above communication method for an inter-domainbidirectional tunnel.

The embodiments of the present disclosure further provide acomputer-readable storage medium having one or more first computerprograms and second computer programs stored therein; the one or morefirst computer programs are executable by one or more processors toimplement the steps of the above method for creating an inter-domainbidirectional tunnel; and the one or more second computer programs areexecutable by one or more processors to implement the steps of the abovecommunication method for an inter-domain bidirectional tunnel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a bidirectional SR tunnel model.

FIG. 2 is a flowchart illustrating a method for creating an inter-domainbidirectional tunnel according to an embodiment of the presentdisclosure.

FIG. 3 is a flowchart illustrating a communication method for aninter-domain bidirectional tunnel according to an embodiment of thepresent disclosure.

FIG. 4 shows an SR-TP inter-domain peer-to-peer model of Border linkaccording to an embodiment of the disclosure.

FIG. 5 shows a format of a stitching LSP association type-length-value(TLV) according to an embodiment of the present disclosure.

FIG. 6 shows an SR-TP inter-domain peer-to-peer model of Border nodeaccording to an embodiment of the present disclosure.

FIG. 7 is a schematic structural diagram of a device for creating aninter-domain bidirectional tunnel according to an embodiment of thepresent disclosure.

FIG. 8 is a schematic structural diagram of a communication device foran inter-domain bidirectional tunnel according to an embodiment of thepresent disclosure.

FIG. 9 is a schematic structural diagram of a communication deviceaccording to an embodiment of the disclosure.

DETAILED DESCRIPTION

In order to make the objectives, technical solutions and advantages ofthe present disclosure clearer, the embodiments of the presentdisclosure are further described in detail below in conjunction with thespecific implementations and accompanying drawings. It should beunderstood that the specific embodiments described herein are merelyintended to explain the present disclosure, rather than limiting thepresent disclosure.

Embodiment One

At present, the traffic engineering of an SR network is implemented bydeploying a centralized controller or a PCE, and PCEP is a pathcomputation protocol widely applied to networks, and can also be used asa southbound interface protocol of an SR controller. In order to supportSR tunnels, the IETF provides an extension to SR for applications oftransport networks in draft-cheng-spring-mpls-path-segment-00, anddefines a SR-TP tunnel for the transport networks. A Path SID isintroduced to identify an SR Path, and bidirectional binding isrealized, but the definitions given in the draft can be applied onlyunder single-domain circumstances, and inter-domain circumstances arenot considered in the draft. When the above method is used for aninter-domain situation, a label stack of a path is very long, whichmakes it hard for the apparatus to parse and encapsulate.

An embodiment of the present disclosure proposes a segmented pathsegment to solve the above problem, and the path segment is configuredto indicate a path identifier of a domain where the path segment islocated; the segmented path segment is mapped onto a next path segmentor a forwarding path from path segment to next domain at a domainboundary; the mapping between the path segment and the next path segmentor between the path segment and the forwarding path from path segment tonext domain is realized by extending an association type, which includesbidirectional label switched path (LSP) association and stitching LSPassociation, the bidirectional LSP association is used forbidirectional-tunnel path binding on a head node and a tail node, andthe stitching LSP association is used for LSP splicing betweeninter-domain boundary nodes; and the stitching LSP association isexpressed in an association type-length-value (TLV) format, whichincludes association type, association id, etc.

FIG. 2 is a flowchart illustrating a method for creating an inter-domainbidirectional tunnel according to an embodiment of the presentdisclosure. The creation method includes steps S201 and S202.

At the step S201, receiving a path creation message sent by a PCE or ahierarchical path element.

At this step, the path creation message is sent mainly in the form of aninter-domain path creation PCInitiate message. The description below isgiven by taking sending PCInitiate messages as an example. In additionto the PCInitiate message, the path creation message can be othermessages, as long as those messages are supported by node communicationor links.

The PCInitiate message is a message for creating an inter-domain path,and includes mapping path information for creating an inter-domain LSP,and bidirectional tunnel instruction information, the mapping pathinformation for the inter-domain LSP includes path segment information,and the bidirectional tunnel instruction information includes anassociation type of the path segment information, and the associationtype is configured to identify whether the path segment information isinter-domain bidirectional path segment information or intra-domainbidirectional path information.

The path segment information includes intra-domain path segmentinformation, or intra-domain path segment information and inter-domainpath segment information.

The association type includes bidirectional LSP association used forbidirectional-tunnel path binding on a head node and a tail node, andstitching LSP association used for LSP splicing between inter-domainboundary nodes.

At the step S202, obtaining an actual transmission path based on themapping path information and the bidirectional tunnel instructioninformation.

The actual transmission path is used for data transmission betweenintra-domain or inter-domain nodes.

In this embodiment, a node receives the PCInitiate message through thehierarchical PCEP. In some embodiments, two types of path segmentinformation, namely intra-domain path segment information andinter-domain path segment information, are simultaneously received by anode, the intra-domain path segment information includes intra-domainforward path segment information and intra-domain reverse path segmentinformation, and the inter-domain path segment information includesinter-domain forward path segment information and inter-domain reversepath segment information.

In this embodiment, the node acquires different pieces of path segmentinformation by receiving one or more PCInitiate messages. A total numberof the PCInitiate messages received is specified according to aprocessing rule of the PCE.

For the path segment information received by the node, at least one ofthe following conditions are met: the path segment information includesintra-domain forward path segment information and intra-domain reversepath segment information, the path segment information includesinter-domain forward path segment information and intra-domain reversepath segment information, and the path segment information includesintra-domain forward path segment information and inter-domain reversepath segment information.

The node processes the received path segment information according tothe association type carried in the received PCInitiate message. If acurrent domain-boundary node is an ingress boundary node or an egressboundary node, the association type is bidirectional LSP association,which indicates that the forward path segment information and thereverse path segment information received by the node belong tointra-domain path segment information. In such case, the path isdirectly determined according to a preset intra-domain path computationrule. In some embodiments, a corresponding bidirectional-tunnel pathsegment is calculated according to the bidirectional LSP association andthe intra-domain path computation rule, and the actual transmission pathis determined based on the bidirectional-tunnel path segment and isbound.

If the current domain-boundary node is an inter-domain boundary node,the association type is stitching LSP association, which indicates thata next communicate node relative to the inter-domain boundary node is aboundary node in another domain, and the path segment informationreceived by the inter-domain boundary node includes intra-domain pathsegment information and inter-domain path segment information, theintra-domain path segment information is path segment information fromthe current node to a previous intra-domain node, and the inter-domainpath segment information is a forwarding path from the current node tothe boundary node in another domain.

The step of obtaining the actual transmission path based on the mappingpath information and the bidirectional tunnel instruction informationincludes splicing the intra-domain path segment information and theforwarding path according to the stitching LSP association to generatean inter-domain bidirectional mapped path and an inter-domainbidirectional-tunnel path segment.

In practical applications, the information about the stitching LSPassociation is stored as data in a TLV format in the PCInitiate messageand sent along with the PCInitiate message, and the TLV format includesa Type field, a Length field, and a Reserved field. As shown in FIG. 5,a Type field is 16 bits long, and a value indicating that this TLV is aTLV of stitching LSP association is assigned relying on InternetAssigned Numbers Authority (IANA) of the IETF; a value of a Length fieldis 4, which indicates that this TLV is 4 bytes; and a Reserved field isa field reserved for later extensions.

In this embodiment, the PCE includes a parent PCE and a child PCE, theparent PCE (H-PCE) is configured to perform inter-domain pathcomputation and traffic scheduling, the child PCE is configured toreceive inter-domain path segment information sent by the H-PCE, performpath computation and traffic scheduling within a domain where the childPCE is located, and then send the inter-domain path segment informationand intra-domain path segment information to a corresponding node. Inpractical applications, the H-PCE is connected to and exchangesinformation with PCE1, PCE2, and PCE3 via the hierarchical PCEP.

In some embodiments, the child PCE acquires a first PCInitiate messagecarrying inter-domain path segment information from the parent PCEthrough the PCEP; and the child PCE calculates path segment informationbetween the nodes within the domain where the child PCE is locatedaccording to an intra-domain node path computation rule, generates asecond PCInitiate message, and sends the second PCInitiate message to acorresponding node; or the child PCE encapsulates the calculated pathsegment information between the nodes within the domain in the firstPCInitiate message, and then sends the first PCInitiate message to thecorresponding node.

With the creation method of an inter-domain bidirectional tunnelprovided by this embodiment, the node receives the PCInitiate message,which includes the mapping path information for creating an inter-domainLSP and the bidirectional tunnel instruction information, from the PCE,and obtains the actual transmission path, which is used for the datatransmission between the intra-domain or inter-domain nodes, based onthe mapping path information and the bidirectional tunnel instructioninformation; by sending mapping path information used for configuringsegments, the node can obtain the previous path segment and the nextpath segment from the mapping path information, and subject the two pathsegments to re-association and encapsulation, thereby creating abidirectional tunnel; and a label stack of the created path isrelatively simple, so that it is easy for the node to search and parseduring data transmission, which greatly increases efficiencies ofservice deployment and data transmission, and also improves userexperience.

Embodiment Two

FIG. 3 illustrates a communication method of an inter-domainbidirectional tunnel according to an embodiment of the presentdisclosure. In the communication method, the creation of an inter-domainbidirectional tunnel is implemented with the method provided by theEmbodiment One. After a tunnel is created based on the method providedby the Embodiment One, a node can perform inter-domain data transmissionthrough corresponding search or data encapsulation.

In this embodiment, the processing steps of the communication methodinclude steps S301 to S303.

At the step S301, receiving a path creation message sent by a PCE or ahierarchical path element.

At this step, the path creation message is sent mainly in the form of aninter-domain path creation PCInitiate message. The description below isgiven by taking sending PCInitiate messages as an example. In additionto the PCInitiate message, the path creation message can be othermessages, as long as those messages are supported by node communicationor links.

The PCInitiate message is a message for creating an inter-domain path,and includes mapping path information for creating an inter-domain LSP,and bidirectional tunnel instruction information, the mapping pathinformation for the inter-domain LSP includes path segment information,and the bidirectional tunnel instruction information includes anassociation type of the path segment information, and the associationtype is configured to identify whether the path segment information isinter-domain bidirectional path segment information or intra-domainbidirectional path information.

The path segment information includes intra-domain path segmentinformation, or intra-domain path segment information and inter-domainpath segment information.

The association type includes bidirectional LSP association used forbidirectional-tunnel path binding on a head node and a tail node, andstitching LSP association used for LSP splicing between inter-domainboundary nodes.

At the step S302, obtaining an actual transmission path based on themapping path information and the bidirectional tunnel instructioninformation.

At the step S303, sending to-be-transmitted data by a node to a nextnode based on the actual transmission path.

In this embodiment, when the node receives the PCInitiate message, thepath segment information in the PCInitiate message is generated throughthe hierarchical PCEP. In some embodiments, two types of path segmentinformation, namely intra-domain path segment information andinter-domain path segment information, are simultaneously received by anode, the intra-domain path segment information includes intra-domainforward path segment information and intra-domain reverse path segmentinformation, and the inter-domain path segment information includesinter-domain forward path segment information and inter-domain reversepath segment information.

In this embodiment, the node acquires different pieces of path segmentinformation by receiving one or more PCInitiate messages. A total numberof the PCInitiate messages received is specified according to aprocessing rule of the PCE.

For the path segment information received by the node, at least one ofthe following conditions are met: the path segment information includesintra-domain forward path segment information and intra-domain reversepath segment information, the path segment information includesinter-domain forward path segment information and intra-domain reversepath segment information, and the path segment information includesintra-domain forward path segment information and inter-domain reversepath segment information.

The node processes the received path segment information according tothe association type carried in the received PCInitiate message. If theassociation type includes the bidirectional LSP association, whichindicates that the forward path segment information and the reverse pathsegment information received by the node belong to intra-domain pathsegment information, the path is directly determined according to apreset intra-domain path computation rule. In some embodiments, acorresponding bidirectional-tunnel path segment is calculated accordingto the bidirectional LSP association and the intra-domain pathcomputation rule, and the actual transmission path is determined basedon the bidirectional-tunnel path segment and is bound

If the association type includes the stitching LSP association, it isindicated that the node is a boundary node, a next communication noderelative to the node is a boundary node in another domain, the pathsegment information received by the node includes intra-domain pathsegment information and inter-domain path segment information, theintra-domain path segment information is path segment information fromthe current node to a previous intra-domain node, and the inter-domainpath segment information is a forwarding path from the current node tothe boundary node in another domain.

In this embodiment, the nodes include three types of nodes, that is,ingress nodes, domain-boundary nodes, and egress nodes, and thedifferent types of nodes are subjected to different forwardingprocesses. Therefore, the method further includes determining a type ofthe current node, and performing a data forwarding process according tothe type of the node.

In this embodiment, in the case where the node is an ingress node, themethod further includes acquiring, encapsulating and forwarding, by theingress node, an SR list of a boundary node of a domain where theingress node is located and a corresponding sub-path segment label.

In the case where the node is a domain-boundary node, a step of sendingthe to-be-transmitted data by the node to the next node based on themapped path includes that the boundary node searches for correspondingforwarding path segment label information to a next domain and an SRlist of the next domain using a path segment label of the domain wherethe node is located according to a binding relationship of the mappedpath, performs data encapsulation according to the obtained information,and forwards the data to the next node.

In the case where the node is an egress node, a step of sending theto-be-transmitted data by the node to the next node based on the mappedpath includes that the egress node searches for a corresponding reversepath segment and reverse path segment label information using a pathsegment label of the domain where the node is located according to abinding relationship of the mapped path, performs data encapsulationaccording to the obtained information, and forwards the data along areverse path.

In practical applications, the nodes of different types are subjected todifferent operation processes. The ingress node encapsulates an SR listfrom the ingress node to a boundary node and a path SID of the domainwhere the ingress node is located, the SR list is configured to instructa packet to be forwarded from the ingress node to the boundary node; theboundary node takes the path SID of the domain where the boundary nodeis located as a keyword, searches for path SID information of the nextdomain and SR list information of the next domain, or path forwardinginformation between boundaries using the keyword according to astitching association binding relationship and the PCInitiate message,encapsulates the obtained information, and forwards it to a next SRnode; and the egress node takes a path SID of the domain where theegress node is located as a keyword, searches for reverse pathinformation and reverse SID information using the keyword according to abidirectional association relationship and the PCInitiate message,encapsulates the obtained information, and forwards it along a reversepath.

With the communication method of an inter-domain bidirectional tunnelprovided by this embodiment, the node receives the PCInitiate message,which includes the mapping path information for creating an inter-domainLSP and the bidirectional tunnel instruction information, from the PCE,and obtains the actual transmission path, which is used for the datatransmission between the intra-domain or inter-domain nodes, based onthe mapping path information and the bidirectional tunnel instructioninformation; by sending mapping path information used for configuringsegments, the node can obtain the previous path segment and the nextpath segment from the mapping path information, and subject the two pathsegments to re-association and encapsulation, thereby creating abidirectional tunnel; and a label stack of the created path isrelatively simple, so that it is easy for the node to search and parseduring data transmission, which greatly increases efficiencies ofservice deployment and data transmission, and also improves userexperience.

Embodiment Three

The creation method of an inter-domain bidirectional tunnel and thecommunication method of an inter-domain bidirectional tunnel areillustrated in detail below in conjunction with application scenarios.FIG. 4 shows an inter-domain SR-TP network diagram, the nodes in whichbelong to a SR-TP inter-domain peer-to-peer model of border link, thenetwork is divided into three autonomous system (AS) domains, the nodesA and B belong to the AS1 domain and are controlled by PCE1 through thePCEP, the nodes C and X belong to the AS2 domain and are controlled byPCE2 through the PCEP, and the nodes Y and Z belong to the AS3 domainand are controlled by PCE3 through the PCEP. The boundary nodes B and Cof AS1 and AS2 are connected by a link, and belong to AS1 and AS2respectively; and the boundary nodes X and Y of AS2 and AS3 are alsoconnected by a link, and belong to AS2 and AS3 respectively. H-PCErealizes inter-domain path computation and traffic scheduling, and isconnected to and exchanges information with PCE1, PCE2 and PCE3 throughthe hierarchical PCEP.

In FIG. 4, path1, path2, path3, path4, and path5 are segmented pathsegments proposed by the present disclosure, the path1, the path3, andthe path5 are used as bidirectional-tunnel path identifiers within AS1,AS2, and AS3 respectively, and the path2 and the path4 are used as abidirectional-tunnel path identifier between AS1 and AS2 and abidirectional-tunnel path identifier between AS2 and AS3, respectively.

According to the tunnel creation method provided by the embodiments ofthe present disclosure, PCE1 sends a PCInitiate message carrying an LSPobject and an association object to the node A, with the LSP objectcarrying a TLV of the segmented path segment path1, and the associationobject carrying a TLV of stitching LSP association in which a Type fieldis a stitching LSP association group (a value of which is assignedrelying on the IANA of the IETF). FIG. 5 shows the format of the TLV ofstitching LSP association, in which a Type field is 16 bits long, and avalue indicating that this TLV is a TLV of stitching LSP association isassigned relying on the IANA of the IETF; a value of a Length field is4, which indicates that this TLV is 4 bytes; and a Reserved field is afield reserved for later extensions.

According to the tunnel creation method provided by the embodiments ofthe present disclosure, PCE1 sends a PCInitiate message which carriesthe path1, an LSP tunnel path LSP1 from A to B, and a TLV of stitchingLSP association to the node B, meanwhile HPCE sends the path2 and astitching LSP association id ID1 to PCE1, and PCE1 sends the path2, alabel from B to C Label B-C, and the ID1, which are sent by HPCE, to thenode B. Since the stitching LSP association ids sent to the node B twiceare the same, the node B performs a splicing process on the label andthe path information, which are sent to the node B twice, maps onto thepath2 and the Label B-C using the path1 as an incoming label, that is,the node B removes the path1 away and encapsulates the Label B-C and thepath2 when the node B receives a segment having a value equal to thepath1, the Label B-C is configured to instruct data to be forwarded fromthe node B to the node C, and the path2 is configured to indicate abidirectional-tunnel path between the node B and the node C.

Embodiments Four

Specific processes and methods of the present disclosure are describedin conjunction with the SR-TP peer-to-peer model of border link.

With reference to FIG. 4, supposing that a PCE initiates the creation ofan LSP in this embodiment, a process of information interaction betweenHPCE and PCE1, PCE2, and PCE3 includes the following steps (1) to (8)according to the present disclosure.

At the step (1), H-PCE sends a PCInitiate message to PCE1, the messagecarrying path2 which is forward path segment information, stitching LSPassociation id1, and a path label from B to C Label B-C.

At the step (2), H-PCE sends a PCInitiate message to PCE1, the messagecarrying path2′ which is reverse path segment information, and stitchingLSP association id1′.

At the step (3), H-PCE sends a PCInitiate message to PCE2, the messagecarrying the path2, and the stitching LSP association id1.

At the step (4), H-PCE sends a PCInitiate message to PCE2, the messagecarrying the path2′, the stitching LSP association id1′, and a pathlabel from C to B Label C-B.

At the step (5), H-PCE sends a PCInitiate message to PCE2, the messagecarrying path4, the stitching LSP association id1, and a path label fromX to Y Label X-Y.

At the step (6), H-PCE sends a PCInitiate message to PCE2, the messagecarrying the path4, and the stitching LSP association id1′.

At the step (7), H-PCE sends a PCInitiate message to PCE3, the messagecarrying the path4 and the stitching LSP association id1.

At the step (8), H-PCE sends a PCInitiate message to PCE3, the messagecarrying the path4′, the stitching LSP association id1′, and a pathlabel from Y to X Label Y-X.

In this embodiment, after receiving the PCInitiate messages sent byH-PCE, each PCE needs to forward the PCInitiate messages to acorresponding node within a domain where the PCE is located, and thenode performs mapping adaptation and encapsulation for an inter-domainpath or an intra-domain path according to the corresponding PCInitiatemessages. In FIG. 4, a process of information interaction between PCE1,PCE2, and PCE3 and the SR nodes A, B, C, X, Y, and Z includes thefollowing steps (1) to (16).

At the step (1), PCE1 sends a PCInitiate message to the node A, themessage carrying path1, an A-B (i.e., from A to B) LSP ID, an A-B LSP SRlist, and a bidirectional LSP association id1.

At the step (2), PCE1 sends a PCInitiate message to the node A, themessage carrying path1′, a B-A LSP ID, and a bidirectional LSPassociation id1′.

At the step (3), PCE1 sends a PCInitiate message to the node B, themessage carrying the path1, the A-B LSP ID, and the stitching LSPassociation id1.

At the step (4), PCE1 sends a PCInitiate message to the node B, themessage carrying the path1′, the B-A LSP ID, a B-A LSP SR list, and thestitching LSP association id1′.

At the step (5), PCE1 sends a PCInitiate message to the node B, themessage carrying the path2, the Label B-C, and the stitching LSPassociation id1.

At the step (6), PCE2 sends a PCInitiate message to the node C, themessage carrying the path2′, the Label C-B, and the stitching LSPassociation id1′.

At the step (7), PCE2 sends a PCInitiate message to the node C, themessage carrying path3, a C-X LSP ID, a C-X LSP SR list, and thestitching LSP association id1.

At the step (8), PCE2 sends a PCInitiate message to the node C, themessage carrying path3′, an X-C LSP ID, and the stitching LSPassociation id1′.

At the step (9), PCE2 sends a PCInitiate message to the node X, themessage carrying the path3, the C-X LSP ID, and the stitching LSPassociation id1.

At the step (10), PCE2 sends a PCInitiate message to the node X, themessage carrying the path3′, the X-C LSP ID, an X-C LSP SR list, and thestitching LSP association id1′.

At the step (11), PCE2 sends a PCInitiate message to the node X, themessage carrying the path4, the Label X-Y, and the stitching LSPassociation id1.

At the step (12), PCE3 sends a PCInitiate message to the node Y, themessage carrying the path4′, the Label Y-X, and the stitching LSPassociation id1′.

At the step (13), PCE3 sends a PCInitiate message to the node Y, themessage carrying path5, a Y-Z LSP ID, a Y-Z LSP SR list, and thestitching LSP association id1.

At the step (14), PCE3 sends a PCInitiate message to the node Y, themessage carrying path5′, a Z-Y LSP ID, and the stitching LSP associationid1′.

At the step (15), PCE3 sends a PCInitiate message to the node Z, themessage carrying the path5, the Y-Z LSP ID, and the bidirectional LSPassociation id1′.

At the step (16), PCE3 sends a PCInitiate message to the node Z, themessage carrying the path5′, the Z-Y LSP ID, a Z-Y LSP SR list, and thebidirectional LSP association id1′.

Each of the nodes B, C, X, and Y performs a path splicing processaccording to the same stitching LSP association ids, maps the path SIDof the domain where the node is located onto the path SID and the SRlist path (or inter-domain label) of a next domain or onto theinter-domain path SID and the inter-domain SR list path (or inter-domainlabel).

The head node A and the tail node Z perform bidirectional-tunnel pathbinding according to the same bidirectional LSP association ids.

According to the above information about a forwarding table, a dataforwarding process of the inter-domain SR-TP of border link of thepresent disclosure includes the following steps (101) to (106).

At the step (101), the head node A encapsulates the A-B SR list (i.e.,the SR list from A to B) and the path1 into a packet, and forwards thepacket to the node B according to the SR list.

At the step (102), after receiving the packet sent by the node A, thenode B searches mapping information in the forwarding table according tothe path1 to obtain the path2 and the Label B-C, encapsulates the LabelB-C and the path2 into the packet, and forwards the packet to the node Caccording to the Label B-C.

At the step (103), after receiving the packet sent by the node B, thenode C searches the mapping information in the forwarding tableaccording to the path2 to obtain the path3 and the C-X SR list,encapsulates the C-X SR list and the path3 into the packet, and forwardsthe packet to the node X according to the SR list.

At the step (104), after receiving the packet sent by the node C, thenode X searches the mapping information in the forwarding tableaccording to the path3 to obtain the path4 and the Label X-Y,encapsulates the Label X-Y and the path4 into the packet, and forwardsthe packet to the node Y according to the Label X-Y.

At the step (105), after receiving the packet sent by the node X, thenode Y searches the mapping information in the forwarding tableaccording to the path4 to obtain the path5 and the Y-Z SR list,encapsulates the Y-Z SR list and the path5 into the packet, and forwardsthe packet to the node Z according to the SR list.

At the step (106), after receiving the packet, the node Z performsloopback operation according to the path 5.

A process of forwarding a packet along a reverse path is similar to theabove process, and thus will not be described in detail. In this way,packet forwarding along the SR-TP bidirectional tunnel is completed.

Embodiment Five

Another type of node exists in the embodiments of the presentdisclosure, that is, a node that simultaneously belongs to two differentdomains. The specific processes of the tunnel creation method of thepresent disclosure in the case of this type of node is described in thisembodiment in conjunction with an SR-TP peer-to-peer model of bordernode.

As shown in FIG. 6, a network is divided into three AS domains, thenodes A and X belong to the AS1 domain and are controlled by PCE1through the PCEP, the nodes X and Y belong to the AS2 domain and arecontrolled by PCE2 through the PCEP, and the nodes Y and Z belong to theAS3 domain and are controlled by PCE3 through the PCEP. The node X islocated on a boundary of the AS1 domain and the AS2 domain, and the nodeY is located on a boundary of the AS2 domain and the AS3 domain. H-PCErealizes inter-domain path computation and traffic scheduling, and isconnected to and exchanges information with PCE1, PCE2 and PCE3 throughthe hierarchical PCEP.

In FIG. 6, path1, path2, and path3 are segmented path segments proposedby the present disclosure, and are used as bidirectional-tunnel pathidentifiers of the AS1 domain, the AS2 domain and the AS3 domain,respectively. Supposing that a PCE initiates the creation of an LSP inthis embodiment, a process of information interaction between PCE1,PCE2, and PCE3 and the SR nodes A, X, Y, and Z includes the followingsteps (1) to (12).

At the step (1), PCE1 sends a PCInitiate message to the node A, themessage carrying path1, an A-X LSP ID, an A-X LSP SR list, and abidirectional LSP association id1.

At the step (2), PCE1 sends a PCInitiate message to the node A, themessage carrying path1′, an X-A LSP ID, and a bidirectional LSPassociation id1′.

At the step (3), PCE1 sends a PCInitiate message to the node X, themessage carrying the path1, the A-X LSP ID, and a stitching LSPassociation id1.

At the step (4), PCE1 sends a PCInitiate message to the node X, themessage carrying the path1′, the X-A LSP ID, an X-A LSP SR list, and astitching LSP association id1′.

At the step (5), PCE2 sends a PCInitiate message to the node X, themessage carrying path2, an X-Y LSP ID, an X-Y LSP SR list, and thestitching LSP association id1.

At the step (6), PCE2 sends a PCInitiate message to node X, the messagecarrying path2′, a Y-X LSP ID, and the stitching LSP association id1′.

At the step (7), PCE2 sends a PCInitiate message to the node Y themessage carrying the path2, the X-Y LSP ID, the X-Y LSP SR list, and thestitching LSP association id1.

At the step (8), PCE2 sends a PCInitiate message to the node Y, themessage carrying the path2′, the Y-X LSP ID, a Y-X LSP SR list, and thestitching LSP association id1′.

At the step (9), PCE3 sends a PCInitiate message to the node Y, themessage carrying path3, a Y-Z LSP ID, a Y-Z LSP SR list, and thestitching LSP association id1.

At the step (10), PCE3 sends a PCInitiate message to the node Y, themessage carrying path3′, a Z-Y LSP ID, and the stitching LSP associationid1′.

At the step (11), PCE3 sends a PCInitiate message to the node Z, themessage carrying the path3, the Y-Z LSP ID, and the bidirectional LSPassociation id1.

At the step (12), PCE3 sends a PCInitiate message to the node Z, themessage carrying the path3′, the Z-Y LSP ID, a Z-Y LSP SR list, and thebidirectional LSP association id1′.

For the border nodes X and Y, the processing of the received informationis as follows (taking the node X as an example for illustration): thepath1 is bound with LSP1, the path2 is bound with the LSP2, a splicingprocess is performed according to the same received stitching LSPassociation ids, the path1 is associated with the path2, the node Xsearches, when receiving the path1, for the path2 associated with thepath1 according to the path1, searches for the LSP2 according to thepath2, and then performs inter-domain label encapsulation and mapping.

The head node A and the tail node Z perform bidirectional-tunnel pathbinding according to the same bidirectional LSP association ids.

According to the above information about a forwarding table, a dataforwarding process of the inter-domain SR-TP of border link of thepresent disclosure includes the following steps (101) to (104).

At the step (101), the head node A encapsulates the A-X SR list and thepath1 into a packet, and forwards the packet to the node X according tothe SR list.

At the step (102), after receiving the packet sent by the node A, thenode X searches mapping information in the forwarding table according tothe path1 to obtain the path2 and the X-Y SR list, encapsulates the X-YSR list and the path2 into the packet, and forwards the packet to thenode Y according to the X-Y SR list.

At the step (103), after receiving the packet sent by the node X, thenode Y searches the mapping information in the forwarding tableaccording to the path2 to obtain the path3 and the Y-Z SR list,encapsulates the Y-Z SR list and the path3 into the packet, and forwardsthe packet to the node Z according to the SR list.

At the step (104), after receiving the packet, the node Z performsloopback operation according to the path3.

A process of forwarding a packet along a reverse path is similar to theabove process, and thus will not be described in detail. In this way,packet forwarding along the SR-TP bidirectional tunnel of Border node iscompleted.

Embodiment Six

FIG. 7 shows a device for creating an inter-domain bidirectional tunnelaccording to an embodiment of the present disclosure. The deviceincludes a receiving module 71 configured to receive a path creationmessage which is sent by a PCE or a hierarchical path element andincludes mapping path information for creating an inter-domain LSP, andbidirectional tunnel instruction information; and a path creating module72 configured to obtain an actual transmission path, which is used forthe data transmission between the intra-domain or inter-domain nodes,based on the mapping path information and the bidirectional tunnelinstruction information.

In this embodiment, the mapping path information for the inter-domainLSP includes path segment information, and the bidirectional tunnelinstruction information includes an association type of the path segmentinformation, and the association type is configured to identify whetherthe path segment information is inter-domain bidirectional path segmentinformation or intra-domain bidirectional path information.

The path segment information includes intra-domain path segmentinformation, or intra-domain path segment information and inter-domainpath segment information.

The association type includes bidirectional LSP association used forbidirectional-tunnel path binding on a head node and a tail node, andstitching LSP association used for LSP splicing between inter-domainboundary nodes.

If the association type includes the bidirectional LSP association,which indicates that the forward path segment information and thereverse path segment information received by a node belong tointra-domain path segment information, the path is directly determinedaccording to a preset intra-domain path computation rule. In someembodiments, the path creating module 72 calculates a correspondingbidirectional-tunnel path segment according to the bidirectional LSPassociation and the intra-domain path computation rule, and determinesand binds the actual transmission path based on the bidirectional-tunnelpath segment.

If the association type includes the stitching LSP association, it isindicated that the node is a boundary node, a next communication noderelative to the node is a boundary node in another domain, the pathsegment information received by the node includes intra-domain pathsegment information and inter-domain path segment information, theintra-domain path segment information is path segment information fromthe current node to a previous intra-domain node, and the inter-domainpath segment information is a forwarding path from the current node tothe boundary node in another domain.

The path creating module 72 splices the intra-domain path segmentinformation and the forwarding path according to the stitching LSPassociation to generate an inter-domain bidirectional mapped path and aninter-domain bidirectional-tunnel path segment.

In this embodiment, the stitching LSP association is stored as data in aTLV format in the path creation message and sent along with the pathcreation message, and the TLV format includes a Type field, a Lengthfield, and a Reserved field.

In this embodiment, the path creation message is sent mainly in the formof an inter-domain path creation PCInitiate message. The descriptionbelow is given by taking sending PCInitiate messages as an example. Inaddition to the PCInitiate message, the path creation message can beother messages, as long as those messages are supported by nodecommunication or links.

In practical applications, the PCE includes a parent PCE and a childPCE, the parent PCE (H-PCE) is configured to perform inter-domain pathcomputation and traffic scheduling, the child PCE is configured toreceive inter-domain path segment information sent by the H-PCE, performpath computation and traffic scheduling within a domain where the childPCE is located, and then send the inter-domain path segment informationand intra-domain path segment information to a corresponding node. Inpractical applications, the H-PCE is connected to and exchangesinformation with PCE1, PCE2, and PCE3 via the hierarchical PCEP. In someembodiments, the child PCE acquires a first PCInitiate message carryinginter-domain path segment information from the parent PCE through thePCEP; and the child PCE calculates path segment information between thenodes within the domain where the child PCE is located according to anintra-domain node path computation rule, generates a second PCInitiatemessage, and sends the second PCInitiate message to a correspondingnode; or the child PCE encapsulates the calculated path segmentinformation between the nodes within the domain in the first PCInitiatemessage, and then sends the first PCInitiate message to thecorresponding node.

According to the device for creating an inter-domain bidirectionaltunnel provided by this embodiment, the device receives the PCInitiatemessage, which includes the mapping path information for creating aninter-domain LSP and the bidirectional tunnel instruction information,from the PCE, and obtains the actual transmission path, which is usedfor the data transmission between the intra-domain or inter-domainnodes, based on the mapping path information and the bidirectionaltunnel instruction information; by sending mapping path information usedfor configuring segments, the node can obtain the previous path segmentand the next path segment from the mapping path information, and subjectthe two path segments to re-association and encapsulation, therebycreating a bidirectional tunnel; and a label stack of the created pathis relatively simple, so that it is easy for the node to search andparse during data transmission, which greatly increases efficiencies ofservice deployment and data transmission, and also improves userexperience.

Embodiment Seven

FIG. 8 is a schematic structural diagram of a communication device foran inter-domain bidirectional tunnel according to an embodiment of thepresent disclosure. The device includes the device for creating aninter-domain bidirectional tunnel 80 provided in the above embodiment,and a data transmission unit 81. The device for creating an inter-domainbidirectional tunnel 80 is configured to receive a path creation messagesent by a PCE or a hierarchical path element, where the path creationmessage includes the mapping path information for creating aninter-domain LSP and the bidirectional tunnel instruction information,and obtain an actual transmission path based on the mapping pathinformation and the bidirectional tunnel instruction information; andthe data transmission unit 81 is configured to transmitto-be-transmitted data from a current node to a next node based on theactual transmission path.

In this embodiment, the device further includes a determination unitconfigured to determine a type of the current node, and the typeincludes an ingress node, a domain-boundary node, and an egress node.

In practical applications, different data forwarding processes areperformed according to different node types. In the case where the nodeis an ingress node, the method further includes acquiring, encapsulatingand forwarding, by the ingress node, an SR list of a boundary node of adomain where the ingress node is located and a corresponding sub-pathsegment label; that is, the ingress node encapsulates an SR list fromthe ingress node to a boundary node and a path SID of the domain wherethe ingress node is located, and the SR list is configured to instruct apacket to be forwarded from the ingress node to the boundary node. Inthe case where the node is a domain-boundary node, a step of sending theto-be-transmitted data by the node to the next node based on the mappedpath includes that the boundary node searches for correspondingforwarding path segment label information to a next domain and an SRlist of the next domain using a path segment label of the domain wherethe node is located according to a binding relationship of the mappedpath, performs data encapsulation according to the obtained information,and forwards the data to the next node.

In this embodiment, the path creation message is sent mainly in the formof an inter-domain path creation PCInitiate message. The descriptionbelow is given by taking sending PCInitiate messages as an example. Inaddition to the PCInitiate message, the path creation message can beother messages, as long as those messages are supported by nodecommunication or links.

In some embodiments, the boundary node takes the path SID of the domainwhere the boundary node is located as a keyword, searches for path SIDinformation of the next domain and SR list information of the nextdomain, or path forwarding information between boundaries using thekeyword according to a stitching association binding relationship andthe PCInitiate message, encapsulates the obtained information, andforwards it to a next SR node.

In the case where the node is an egress node, a step of sending theto-be-transmitted data by the node to the next node based on the mappedpath includes that the egress node searches for a corresponding reversepath segment and reverse path segment label information using a pathsegment label of the domain where the node is located according to abinding relationship of the mapped path, performs data encapsulationaccording to the obtained information, and forwards the data along areverse path.

In some embodiments, the egress node takes a path SID of the domainwhere the egress node is located as a keyword, searches for reverse pathinformation and reverse SID information using the keyword according to abidirectional association relationship and the PCInitiate message,encapsulates the obtained information, and forwards it along a reversepath.

According to the communication device for an inter-domain bidirectionaltunnel, the device receives the PCInitiate message, which includes themapping path information for creating an inter-domain LSP and thebidirectional tunnel instruction information, from the PCE, and obtainsthe actual transmission path, which is used for the data transmissionbetween the intra-domain or inter-domain nodes, based on the mappingpath information and the bidirectional tunnel instruction information;by sending mapping path information used for configuring segments, thenode can obtain the previous path segment and the next path segment fromthe mapping path information, and subject the two path segments tore-association and encapsulation, thereby creating a bidirectionaltunnel; and a label stack of the created path is relatively simple, sothat it is easy for the node to search and parse during datatransmission, which greatly increases efficiencies of service deploymentand data transmission, and also improves user experience.

Embodiment Eight

A communication device is provided in this embodiment. With reference toFIG. 9, the system includes a processor 901, a memory 902, and acommunication bus 903; the communication bus 903 is configured toimplement communication connection between the processor 901 and thememory 902; the processor 901 is configured to execute one or more firstprograms stored in the memory 902 to perform the steps that adomain-boundary node receives a path creation message which is sent by aPCE or a hierarchical path element and includes mapping path informationfor creating an inter-domain LSP, and bidirectional tunnel instructioninformation, and obtains an actual transmission path, which is used fordata transmission between intra-domain or inter-domain nodes, based onthe mapping path information and the bidirectional tunnel instructioninformation.

The processor 901 is further configured to execute one or more secondprograms stored in the memory 902 to perform the following steps:receiving a path creation message which is sent by a PCE or ahierarchical path element and includes mapping path information forcreating an inter-domain LSP, and bidirectional tunnel instructioninformation; obtaining an actual transmission path based on the mappingpath information and the bidirectional tunnel instruction information;and sending to-be-transmitted data by a node to a next node based on theactual transmission path.

In this embodiment, the mapping path information for the inter-domainLSP includes path segment information, and the bidirectional tunnelinstruction information includes an association type of the path segmentinformation, and the association type is configured to identify whetherthe path segment information is inter-domain bidirectional path segmentinformation or intra-domain bidirectional path information.

The path segment information includes intra-domain path segmentinformation, or intra-domain path segment information and inter-domainpath segment information.

The association type includes bidirectional LSP association used forbidirectional-tunnel path binding on a head node and a tail node, andstitching LSP association used for LSP splicing between inter-domainboundary nodes.

In this embodiment, the path creation message is sent mainly in the formof an inter-domain path creation PCInitiate message. The descriptionbelow is given by taking sending PCInitiate messages as an example. Inaddition to the PCInitiate message, the path creation message can beother messages, as long as those messages are supported by nodecommunication or links.

The node acquires different pieces of path segment information byreceiving one or more PCInitiate messages. A total number of thePCInitiate messages received is specified according to a processing ruleof the PCE.

For the path segment information received by the node, at least one ofthe following conditions are met: the path segment information includesintra-domain forward path segment information and intra-domain reversepath segment information, the path segment information includesinter-domain forward path segment information and intra-domain reversepath segment information, and the path segment information includesintra-domain forward path segment information and inter-domain reversepath segment information.

In this embodiment, the method further includes determining a type ofthe current node, and performing a data forwarding process according tothe type of the node.

In the case where the node is an ingress node, the method furtherincludes acquiring, encapsulating and forwarding, by the ingress node,an SR list of a boundary node of a domain where the ingress node islocated and a corresponding sub-path segment label.

In the case where the node is a domain-boundary node, a step of sendingthe to-be-transmitted data by the node to the next node based on themapped path includes that the boundary node searches for correspondingforwarding path segment label information to a next domain and an SRlist of the next domain using a path segment label of the domain wherethe node is located according to a binding relationship of the mappedpath, performs data encapsulation according to the obtained information,and forwards the data to the next node.

In the case where the node is an egress node, a step of sending theto-be-transmitted data by the node to the next node based on the mappedpath includes that the egress node searches for a corresponding reversepath segment and reverse path segment label information using a pathsegment label of the domain where the node is located according to abinding relationship of the mapped path, performs data encapsulationaccording to the obtained information, and forwards the data along areverse path.

Correspondingly, the embodiment of the present disclosure furtherprovides a computer-readable storage medium, includingvolatile/nonvolatile and removable/non-removable media used in anymethod or technology for storing information (such as computer-readableinstructions, data structures, program modules or other data). Thecomputer-readable storage medium includes, but is not limited to, aRandom Access Memory (RAM), a Read-Only Memory (ROM), an ElectricallyErasable Programmable Read-Only Memories (EEPROM), a flash memory orother memories, a Compact Disc Read-Only Memories (CD-ROM), a DigitalVideo Disk (DVD) or another optical disc, a magnetic cassette, amagnetic tape, a magnetic disk or other magnetic storage devices, or anyother medium which can be used to store the desired information and canbe accessed by a computer.

The computer-readable storage medium in this embodiment can beconfigured to store the one or more first computer programs and secondcomputer programs, and the stored one or more first computer programsand second computer programs can be executed by the processor toimplement at least one step of the method for creating an inter-domainbidirectional tunnel in the Embodiment One and the communication methodfor an inter-domain bidirectional tunnel in the Embodiment Two.

This embodiment further provides a computer program, which can bedistributed on a computer readable medium and executed by a computingdevice to implement at least one step of the method in the EmbodimentOne. In some cases, at least one step illustrated or described hereinmay be executed in an order different from that described in theembodiments.

This embodiment further provides a computer program product, including acomputer readable device having the above computer program storedtherein. In this embodiment, the computer readable device may includethe above computer-readable storage medium.

To sum up, with the method and the device for creating an inter-domainbidirectional tunnel, the communication method and the communicationdevice for an inter-domain bidirectional tunnel, and thecomputer-readable storage medium provided by the embodiments of thepresent disclosure, the node receives the PCInitiate message, whichincludes the mapping path information for creating an inter-domain LSPand the bidirectional tunnel instruction information, from the PCE, andobtains the actual transmission path, which is used for the datatransmission between the intra-domain or inter-domain nodes, based onthe mapping path information and the bidirectional tunnel instructioninformation; by sending mapping path information used for configuringsegments, the node can obtain the previous path segment and the nextpath segment from the mapping path information, and subject the two pathsegments to re-association and encapsulation, thereby creating abidirectional tunnel; and a label stack of the created path isrelatively simple, so that it is easy for the node to search and parseduring data transmission, which greatly increases efficiencies ofservice deployment and data transmission, and also improves userexperience.

It should be understood by those of ordinary skill in the art that thefunctional modules/units in all or some of the steps, the systems, andthe devices in the methods disclosed above may be implemented assoftware (which may be implemented as computer program codes executableby a computing device), firmware, hardware, or suitable combinationsthereof. If implemented as hardware, the division between the functionalmodules/units stated above is not necessarily corresponding to thedivision of physical components; for example, one physical component mayhave a plurality of functions, or one function or step may be performedthrough cooperation of several physical components. Some or all of thephysical components may be implemented as software executed by aprocessor, such as a central processing unit, a digital signal processoror a microprocessor, or may be implemented as hardware, such as anapplication specific integrated circuit.

In addition, it is well known by those of ordinary skill in the art thatthe communication media generally include computer-readableinstructions, data structures, program modules or other data in amodulated data signal, such as a carrier wave or other transmissionmechanism, and may include any information delivery media. Therefore,the present disclosure is not limited to any specific combination ofhardware and software.

The above is a further detailed description of the embodiments of thepresent disclosure in conjunction with the specific implementations, butthe specific implementations of the present disclosure are not limitedto the above description. Several simple deductions or substitutions canbe made by those of ordinary skill in the art without departing from theconcept of the present disclosure, and should be considered to fallwithin the scope of the present disclosure.

1. A method for creating an inter-domain bidirectional tunnel,comprising: receiving, by a domain-boundary node, an inter-domain pathcreation PCInitiate message sent by a path computation element (PCE) ora hierarchical path element, the PCInitiate message comprising mappingpath information for creating an inter-domain label switched path (LSP)and bidirectional tunnel instruction information; and obtaining anactual transmission path, which is used for data transmission betweenintra-domain or inter-domain nodes, based on the mapping pathinformation and the bidirectional tunnel instruction information.
 2. Themethod for creating an inter-domain bidirectional tunnel of claim 1,further comprising determining a type of the domain-boundary node,wherein the type comprises an ingress boundary node, an inter-domainboundary node, and an egress boundary node.
 3. The method for creatingan inter-domain bidirectional tunnel of claim 2, wherein the mappingpath information for the inter-domain LSP comprises path segmentinformation, and the bidirectional tunnel instruction informationcomprises an association type of the path segment information.
 4. Themethod for creating an inter-domain bidirectional tunnel of claim 3,wherein the path segment information is acquired by receiving one ormore PCInitiate messages through Path Computation Element CommunicationProtocol (PCEP).
 5. The method for creating an inter-domainbidirectional tunnel of claim 4, wherein the path segment informationcomprises intra-domain path segment information and inter-domain pathsegment information.
 6. The method for creating an inter-domainbidirectional tunnel of claim 5, wherein, in a case where thedomain-boundary node is an ingress boundary node or an egress boundarynode, the association type is bidirectional LSP association; the step ofobtaining the actual transmission path based on the mapping pathinformation and the bidirectional tunnel instruction informationcomprises: calculating a corresponding bidirectional-tunnel path segmentaccording to the bidirectional LSP association and an intra-domain pathcomputation rule; and determining the actual transmission path based onthe bidirectional-tunnel path segment, and binding the path.
 7. Themethod for creating an inter-domain bidirectional tunnel of claim 5,wherein, in a case where the domain-boundary node is an inter-domainboundary node, the association type is stitching LSP association; theintra-domain path segment information is path segment information fromthe domain-boundary node to a previous intra-domain node, and theinter-domain path segment information is a forwarding path from thedomain-boundary node to a domain-boundary node in another domain; thestep of obtaining the actual transmission path based on the mapping pathinformation and the bidirectional tunnel instruction informationcomprises: splicing the intra-domain path segment information and theforwarding path according to the stitching LSP association to generatean inter-domain bidirectional mapped path and an inter-domainbidirectional-tunnel path segment.
 8. The method for creating aninter-domain bidirectional tunnel of claim 7, wherein the stitching LSPassociation is stored as data in a TLV format in the PCInitiate messageand sent along with the PCInitiate message, and the TLV format comprisesa Type field, a Length field, and a Reserved field.
 9. The method forcreating an inter-domain bidirectional tunnel of claim 1, wherein thePCE comprises a parent PCE and a child PCE, and the step of receiving,by the domain-boundary node, the inter-domain path creation PCInitiatemessage sent by the PCE or the hierarchical path element comprises that:the child PCE acquires a first PCInitiate message carrying inter-domainpath segment information from the parent PCE through the PCEP; and thechild PCE calculates path segment information between nodes within adomain where the child PCE is located according to an intra-domain nodepath computation rule, generates a second PCInitiate message, and sendsthe second PCInitiate message to a corresponding node; or the child PCEencapsulates the calculated path segment information between the nodeswithin the domain in the first PCInitiate message, and then sends thefirst PCInitiate message to a corresponding node.
 10. A communicationmethod for an inter-domain bidirectional tunnel, comprising: receiving,by a node, an inter-domain path creation PCInitiate message sent by aPCE or a hierarchical path element, the PCInitiate message comprisingmapping path information for creating an inter-domain LSP andbidirectional tunnel instruction information; obtaining an actualtransmission path based on the mapping path information and thebidirectional tunnel instruction information; and sendingto-be-transmitted data by the node to a next node based on the actualtransmission path.
 11. The communication method for an inter-domainbidirectional tunnel of claim 10, further comprising determining a typeof the node, wherein the type comprises an ingress node, adomain-boundary node, and an egress node.
 12. The communication methodfor an inter-domain bidirectional tunnel of claim 11, in a case wherethe node is an ingress node, further comprising: acquiring,encapsulating and forwarding, by the ingress node, a Segment Routing(SR) list of a domain-boundary node of a domain where the ingress nodeis located and a corresponding sub-path segment label.
 13. Thecommunication method for an inter-domain bidirectional tunnel of claim11, wherein, in a case where the node is a domain-boundary node, thestep of sending the to-be-transmitted data by the node to the next nodebased on the actual transmission path comprises that: the boundary nodesearches for corresponding forwarding path segment label information toa next domain and an SR list of the next domain using a path segmentlabel of a domain where the node is located according to a bindingrelationship of the actual transmission path; and performs encapsulationof data according to obtained information, and forwards the data to thenext node.
 14. The communication method for an inter-domainbidirectional tunnel of claim 11, wherein, in the case where the node isan egress node, the step of sending the to-be-transmitted data by thenode to the next node based on the actual transmission path comprisesthat: the egress node searches for a corresponding reverse path segmentand reverse path segment label information using a path segment label ofa domain where the node is located according to a binding relationshipof the actual transmission path; and performs encapsulation of dataaccording to obtained information, and forwards the data along a reversepath.
 15. A device for creating an inter-domain bidirectional tunnel,comprising: a receiving module configured to receive an inter-domainpath creation PCInitiate message sent by a PCE or a hierarchical pathelement, the PCInitiate message comprising mapping path information forcreating an inter-domain LSP and bidirectional tunnel instructioninformation; and a path creating module configured to obtain an actualtransmission path, which is used for data transmission betweenintra-domain or inter-domain nodes, based on the mapping pathinformation and the bidirectional tunnel instruction information.
 16. Acommunication device for an inter-domain bidirectional tunnel,comprising the device for creating an inter-domain bidirectional tunnelof claim 15, and a data transmission unit; the device for creating aninter-domain bidirectional tunnel is configured to receive aninter-domain path creation PCInitiate message sent by a PCE or ahierarchical path element, the PCInitiate message comprising mappingpath information for creating an inter-domain LSP and bidirectionaltunnel instruction information, and obtain an actual transmission pathbased on the mapping path information and the bidirectional tunnelinstruction information; and the data transmission unit is configured totransmit to-be-transmitted data from a current node to a next node basedon the actual transmission path.
 17. A communication device, comprisinga processor, a memory, and a communication bus; the communication bus isconfigured to implement communication connection between the processorand the memory; the processor is configured to execute one or moreprograms stored in the memory to perform steps of the method forcreating an inter-domain bidirectional tunnel of claim
 1. 18. Acomputer-readable storage medium storing having one or more computerprograms stored therein; the one or more computer programs areexecutable by one or more processors to implement steps of the methodfor creating an inter-domain bidirectional tunnel of claim
 1. 19. Acommunication device, comprising a processor, a memory, and acommunication bus; the communication bus is configured to implementcommunication connection between the processor and the memory; theprocessor is configured to execute one or more programs stored in thememory to perform steps of the communication method for an inter-domainbidirectional tunnel of claim
 10. 20. A computer-readable storage mediumstoring having one or more computer programs stored therein; the one ormore computer programs are executable by one or more processors toimplement steps of the communication method for an inter-domainbidirectional tunnel of claim 10.